Free coal heating in northern China had dramatic health consequences.

Coal is the least efficient of the fossil fuels in terms of the amount of energy gained vs. CO2 released. Burning it also releases numerous toxic chemicals and particulates, which can exact a cost on a country's population in terms of reduced life expectancy and increased health costs. Figuring out the exact cost of coal use, however, is challenging because of a combination of different pollution controls and the mobility of the population.

Thanks to an unusual combination of policies (some completely unrelated to pollution), China has accidentally provided the opportunity to put an exact number on the human cost of coal use. And that number turns out to be staggering: 5.5 years of reduced life expectancy that, when spread over the half-billion people of northern China, means a loss of 2.5 billion life-years.

The Huai River line

There are two key policies that turned China into a giant natural experiment on the impact of coal. The first is that, until recent years, China has had laws in place that severely limited the mobility of its citizenry. People didn't tend to move around, so they continued to live (and die) near the site of their exposure. That makes lifetime exposures easy to estimate, and it ensures that local health and mortality records could be directly connected to these exposures.

Second, starting in 1950, the Chinese government divided the country along the Huai River, which roughly traces the line where winter temperatures are, on average, freezing—and north of that line, everyone was eligible for free, coal-powered heating. The line cuts across a variety of provinces and political divisions, so there's little else about China that's likely to be divided in the same way.

China uses coal for a variety of purposes beyond heating—with the result that, as the authors of a new study note, current particulate levels in China are five times what they were in the US back in the 1960s, prior to the passage of the Clean Air Act. (These levels are, incidentally, twice the limits allowed under Chinese law.) Despite the existing overall high levels of pollution across the country, the addition of this much heating-related coal burning had a significant impact on the air quality of northern China over the last half century. By 2000, as one crossed the Huai River line, the total particulates in each cubic meter of air jumped by nearly 200 micrograms.

Exposure to particulates has a variety of negative consequences, primarily on the lung and cardiovascular systems, so the authors classified all deaths in 90 Chinese cities between 1990-2000 and collected additional demographic information that covered factors that are associated with life expectancies. Then they ran it all through a statistical model that took into account each city's distance from the Huai River. Their model suggests that life expectancies north of the river line are 5.5 years lower than they are to the south (although their 95 percent confidence interval is rather large). Their estimate suggests that every 100 micrograms of particulates in a cubic meter of air drops life expectancy by about three years.

Based on this drop in life expectancy, the authors calculate a total loss of life for the half-billion citizens that live north of the line as 2.5 billion years of life lost prematurely.

The authors do note that the free coal provided by the government would likely alter behavior in a variety of ways, some of which could influence health. People might spend more of their year indoors, get less exercise, have more disposable income, etc. Still, the magnitude of the effect is rather large and is consistent with what we know about the health impacts of particulates.

China is just beginning to grapple with its heavy use of coal and its lack of pollution controls. But the installed base of coal-burning hardware, from large plants to individual homes, remains enormous, which means that there will be a long legacy of health problems inherited from earlier policy decisions.

-- Current and recent days' temperatures were the weather components most strongly predictive of-- mortality, and mortality risk generally decreased as temperature increased from the coldest days-- to a certain threshold temperature, which varied by latitude, above which mortality risk increased-- as temperature increased. The authors also found a strong association of the temperature-mortality-- relation with latitude, with a greater effect of colder temperatures on mortality risk in more-southern-- cities and of warmer temperatures in more-northern cities.

While I did not read more than the abstract, this study is from 2002 it should be able somewhere not behind a paywall.

That study looks at short term mortality associated with heat waves / cold snaps.

The abstract does not seem to be saying this...

-- Episodes of extremely hot or cold temperatures are associated with increased mortality.-- Time-series analyses show an association between temperature and mortality across a-- range of less extreme temperatures.

Quote:

It finds that heat waves in usually cold cities and cold snaps in usually warm cities are the worst killers. None of that compares whether overall there is a life expectancy change for living in a city with average higher/lower temperatures.

I don't see any mention of heat waves or cold snaps in the abstract.

Quote:

My point about life expectancy in Sweden was that it's pretty cold there, and they have among the highest life expectancies of any country. Iceland, Norway, Finland and Canada also rate pretty high.

Firstly, mortality and life expectancy are different things. I just traced back the original statement and it seems that the issue was life expectancy, not mortality per se, so I was barking up the wrong tree. But still there does seem to be some evidence for increased mortality at colder temperatures, and by this I don't mean extreme cold. I've been through my share of that.

-- Weather-related health effects have attracted renewed interest because of the observed-- and predicted climate change. The authors studied the short-term effects of cold weather-- on mortality in 15 European cities. The effects of minimum apparent temperature on -- cause- and age-specific daily mortality were assessed for the cold season (October–March)-- by using data from 1990–2000. For city-specific analysis, the authors used Poisson regression-- and distributed lag models, controlling for potential confounders. Meta-regression models-- summarized the results and explored heterogeneity. A 1°C decrease in temperature was-- associated with a 1.35% (95% confidence interval (CI): 1.16, 1.53) increase in the daily-- number of total natural deaths and a 1.72% (95% CI: 1.44, 2.01), 3.30% (95% CI: 2.61, 3.99),-- and 1.25% (95% CI: 0.77, 1.73) increase in cardiovascular, respiratory, and cerebrovascular-- deaths, respectively. The increase was greater for the older age groups. The cold effect was-- found to be greater in warmer (southern) cities and persisted up to 23 days, with no evidence-- of mortality displacement. Cold-related mortality is an important public health problem across-- Europe. It should not be underestimated by public health authorities because of the recent-- focus on heat-wave episodes.

I also note that a slight increase in mortality caused heat or cold won't have much effect on life expectancy.

-- Despite being home to “the land of the midnight sun,” most people think of winter when-- they hear of Sweden. Because of the warm Gulf Stream, the climate here can be much-- milder than you might expect.

No the headline really is retarded. The figure is so high because the population is also high. That's also the reason for the smog, because the chinese have far lower pollution rates per capita than the US.

No the headline really is retarded. The figure is so high because the population is also high. That's also the reason for the smog, because the chinese have far lower pollution rates per capita than the US.

Maybe, but I don't think your conclusion follows. Don't most of the Chinese cook with coal cakes? I would think that this alone would emit more particulate pollution than most Americans.

-- The US embassy in Beijing regularly posts automated air quality measurements at @beijingair-- on Twitter. On 18 November 2010, the feed described the PM2.5 measurement as "crazy bad"-- after registering a reading in excess of 500 for the first time. This description was later changed-- to "beyond index",[21] a level which recurred in February, October, and December 2011.

-- By January 2013 the pollution had worsened with official Beijing data showing an average figure-- over 300 and readings of up to 700 at individual recording stations while the US Embassy -- recorded over 755 on January 1 and 800 by January 12

So PM2.5 (the wost particulate size) averaged over 300 on Jan 2013.

Let's compare Beijing with Los Angeles, a California city known for it's pollution.

-- The highest particualte matter(PM2.5) in a 24 hour period recorded in Los Angeles County,-- California was 43 micro grams per cubic meter and the weighted annual mean was 14.8 micro-- grams per cubic meter.